Prospective Comparison of the Imaging Value of 99mTc-MDP Bone Scan and 68Ga-FAPI-04 PET/CT in Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis Syndrome

Abstract

Purpose This study aimed to explore the imaging value of 68Ga-FAPI-04 PET/CT in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome and compare it with that of 99mTc-MDP bone scan. Methods Nineteen participants with SAPHO syndrome underwent 68Ga-FAPI-04 PET/CT and 99mTc-MDP bone scan. Demographic data and clinical features were recorded, SAPHO imaging features were analyzed, and the osteoarticular lesion detection rate in both methods was calculated. Results This prospective study recruited 4 men and 15 women aged 52.4 ± 8.6 years. The anterior chest wall was involved in all participants (100%). Palmoplantar pustulosis was the most common (36.8%) skin symptom. 99mTc-MDP bone scan and 68Ga-FAPI-04 PET/CT together detected 84 osteoarticular lesions, of which 91.7% (77/84) were detected by the former and 96.4% (81/84) by the latter. Furthermore, 68Ga-FAPI-04 PET/CT detected 5 cases of knee and hip joint synovitis. Conclusions 68Ga-FAPI-04 PET/CT was more sensitive than 99mTc-MDP bone scan when evaluating osteoarticular lesions in SAPHO syndrome and could also evaluate synovial lesions. 68Ga-FAPI-04 PET/CT could be a good imaging method for SAPHO syndrome but requires further verification in a more extensive research cohort.